Synthese, Struktur und Isomerie stabiler diphosphorylierter Enole

Abstract

Die Hydrolyse der ungesattigten Acyldiphenylphosphanoxide R1R2C = CR3C (0) Au f Grund von Rontgenstrukturanalysen kristallisieren die konstitutionsisomeren Verbindungen (E)-3b und 4b in der monoklinen Raumgruppe P2,/n mit Z = 4. Synthesis, Structure, and Isomerism of Stable Diphosphorylated EnolsUnder addition of the intermediary formed HP(0)Ph2 to the double bond of l a -c the hydrolysis of the unsaturated acyldiphenylphosphane oxides R'R2C = CR3C(0)P(O)Ph2 ( l a -c) yields the E-isomeric phosphorylated enols Ph,(O)P -CR'R2-CR3 = C(OH)P(O)Ph, ((E)-3a -c). At the same time the Z-isomer 3c and, under addition of HP(0)Ph2 to the carbonyl group of l b , also the phosphinate 4 b can be isolated. 3 b,c is also obtained from 1 b,c and HP(O)Ph, or from the acylphosphane R'R2C = CR3C(0)PPh2 (2c) and HP(0)Ph2 under oxidative conditions. The course of the reaction is proved for the example of 1 b using D20 and DP(0)Ph2, respectively which results in the formation of the deuterated enol Ph2(0)P -CR1R2 -CR3 = C(OD)P (0) , ((E)-7d). On the basis of X-ray crystallographic investigations the constitutional isomers (E)-3 b and 4b crystallize in the monoclinic space group P2,/n with Z = 4.In friiheren Arbeiten wurde die ausgepragte Reaktivitat von Acyl-und Aroyl(diary1)-phosphanoxiden gegenuber Nucleophilen ausfiihrlich beschrieben. Sie zeigt sich nicht nur in ihrem Dimerisierungsbestreben1s2), sondern in noch erheblicherem AusmaB in der hohen Affinitat gegeniiber Wasser3-14) oder anderen, ein acides Proton enthalten-0 Verlag Chemie GmbH, D

Phosphinomethanide versus phosphinoenolate: thermodynamical preference for a three- instead of a five-membered chelate ring

“…The bond angles of the three-membered ring are comparable to those found in the osmium analogue of 5 4 and in various [L n M{k 2 (P,C)-Ph 2 PCH 2 }] complexes. 8 The distance P-C( 1) is shorter by ca. 0.08 Å than the distances P-C(4) and P-C(7) indicating a substantial double-bond character of the phosphorus-carbon bond in the RuCP unit.…”